California ADU rules - popularity rank #3
San Jose ADU rules include City and California State paths across detached, attached, garage conversion, conversion, and JADU cases. The structured data preserves source warnings where zoning-table or parcel-specific checks are required.
Based on 18 curated rule paths from official sources. Last reviewed June 2026. Use this page as the rule starting point, then run the address check to see which path matches your lot.
Popularity rank
#3 California ADU market
Rule paths
18 curated ADU rule sets
State detached ADU
Up to 800 sq ft
Side / rear setbacks
4 ft state baseline
Minimum unit size
150 sq ft
Primary source
City of San Jose ADU page
Rule snapshot
These sections mirror the questions homeowners search for: size, setbacks, parking, permit workflow, and which ADU type is available. The rows stay source-backed and avoid turning a city rule into parcel approval.
Planning a garage conversion ADU?
Read the California garage conversion guide, then run the address check to match the city baseline to the actual lot.
Estimating ADU permit cost?
Permit cost depends on the fee stack, ADU type, size, waivers, and plan-check path for this city.
San Jose is a strong example of why city pages need more than one rule card: City and California State standards can point to different limits.
The State path provides the protected baseline; the City path can allow larger detached ADUs when the lot and zoning support it.
San Jose rule rows still need the actual zoning district, lot size, frontage, and project type to become useful for a specific address.
Why this is a starting point
Competitor rule pages often stop at a city summary. The useful next step is matching those rules to an actual lot, because zoning, parcel geometry, overlays, and selected ADU type decide what a homeowner should do next.
San Jose is represented with both local City paths and California State paths, so unlocked reports can compare where size, setback, and placement rules differ.
The state detached ADU path includes 1 ADU, 150 sq ft minimum, up to 800 sq ft, 4 ft side and rear setbacks, and zoning-district front-setback references.
Where a row depends on zoning-table lookup or parcel-specific constraints, the data keeps the caveat in warnings instead of converting it into a yes/no eligibility claim.
Free ADU Check
The city page gets the search visitor in the door. The ADU Check turns the visit into a property-specific report path.
Start free address checkThe check matches the typed address to jurisdiction, zoning, parcel context, and the closest stored ADU rule path.
Detached, attached, conversion, garage conversion, and JADU paths are handled separately when the city source supports them.
The report keeps official rule text separate from parcel-specific caveats, so a homeowner can see the rule and the remaining risk.
Official links
These are outbound official sources from HomeFeasible's reviewed ADU rule collection. They are here for verification and trust; the address check is the next step for a property-specific answer.
Primary rule page
https://www.sanjoseca.gov/business/development-services-permit-center/accessory-dwelling-units-adus
Rule checklist
https://www.sanjoseca.gov/home/showpublisheddocument/39038/639083231101130000
Permit process
https://www.sanjoseca.gov/business/development-services-permit-center/accessory-dwelling-units-adus/adu-plan-review-permit-process
Fee reference
https://www.sanjoseca.gov/your-government/departments-offices/planning-building-code-enforcement/building-division/building-permit-fees
Internal links
Top questions
Summaries reflect official source links and the structured ADU rule data collected for HomeFeasible's first launch. Regulations change and individual parcels vary; verify current requirements with the city planning department or run a parcel-specific check before making decisions.
Canonical URL: https://homefeasible.com/city/san-jose/adu
